21136506 has 16 divisors (see below), whose sum is σ = 43071264. Its totient is φ = 6912464.

The previous prime is 21136501. The next prime is 21136519. The reversal of 21136506 is 60563112.

It is not an unprimeable number, because it can be changed into a prime (21136501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32916 + ... + 33551.

It is an arithmetic number, because the mean of its divisors is an integer number (2691954).

Almost surely, 2^21136506 is an apocalyptic number.

21136506 is an abundant number, since it is smaller than the sum of its proper divisors (21934758).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21136506 is a wasteful number, since it uses less digits than its factorization.

21136506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66525.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 21136506 is about 4597.4455951104. The cubic root of 21136506 is about 276.4889202004.

Adding to 21136506 its reverse (60563112), we get a palindrome (81699618).

The spelling of 21136506 in words is "twenty-one million, one hundred thirty-six thousand, five hundred six".